Automatic yarn piecing and knotting method and apparatus for the open-end spinning machine

ABSTRACT

A yarn piecing and knotting method and its apparatus utilized for the open-end spinning process. A supplementary yarn is utilized in one version, while another version is an application of a similar method to conventional yarn piecing. After completion of the yarn piecing operation, an upstream yarn delivering from a spinning rotor and a downstream yarn unwound from a yarn package are knotted and an excess portion of the upstream yarn which includes the portion containing the yarn piecing operation and a portion of the downstream yarn are cut off.

tied ttes tent [191 1 3,858,385 Shinltai et a1. Jan. 7, 1975 AUTOMATIC YARN lPlEClNG AND 3,455,095 7/1969 Makeham et :al. 57/34 R KNOTTING METHOD AND APPARATUS qi E S11 umo B a FOR THE OPEN-END SPINNING MACHINE 3,540,201 11/1970 Susami et al 57/80 [75] Inventors: Kunio Shinkai, Handa; ll-llazuo 3,640,059 2/1972 Lutovsky et a]. 57/34 R Yamada, lnazawa; Kenji Sakaki, iqlshlkasugfil g Yasuda Primary Examiner-John Petrakes nazawa a O apan Attorney, Agent, or FirmMaleson, Kimmelman & [73] Assignee: Howa Kagyo Kabusliiki Kaisha, Rattler Aichi-ken, Japan [22] Filed: July 1, 1971 [57] ABSTRACT [21] Appl. No: 158,830

A yarn piecing and knotting method and its apparatus utilized for the open-end spinning process. A supple- 1 Foreign Application Priority Dam mentary yarn is utilized in one version, while another July 4, 1970 Japan 45-58144 version is an application of a similar method to conventional yarn piecing. After completion of the yarn [52] 11.8. C1 57/34 R, 57/58.95, 57/80 piecing operation, an upstream yarn delivering from a [51] Int. Cl D0lh 15/00 spinning rotor and a downstream yarn unwound from [58] Field of Search 57/34 R, 58.89-58.95, a yarn package are knotted and an excess portion of 57/78, 80; 242/355 R, 35.5 A the upstream yarn which includes the portion containing the yarn piecing operation and a portion of the [56] References Cited downstream yarn are cut off.

UNITED STATES PATENTS 3,077,311 13 Claims, 27 Drawlng Figures 2/1963 Furst 242/355 R Patented Jan. 7, 1975 11 Sheets-Sheet 1 Patented Jan. 7 1975 ll Sheets-Sheet 2 Patented Jan. 7, 1975 ll Sheets-Sheet 5 Patented Jan. 7, 1975 3,858,385

11 Sheets-Sheet 4.

Patented Jan. 7, 1975 3,858,385

' 11 Sheets-Sheet 5 Patented Jan. 7,1975

11 Sheets-Sheet 6 Patented Jan. 7, 1975 3,858,385

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11 Sheets-Sheet 10 Patented Jan. 7, 1975 ll Sheets-Sheet l1 AUTOMATIC YARN PTECTNG AND KNOTTING METHOD AND APPARATUS FOR THE OPEN-END SPINNING MACHINE BRIEF SUMMARY OF THE INVENTION The present invention relates to an automatic yarn piecing and knotting method and apparatus for the open-end spinning machine which is characterized by a spinning rotor to which liberated fibers are continuously supplied for accumulation of above-mentioned liberated fibers upon an accumulation surface formed therein and from which a yarn having twists is continuously delivered by a take-up means so as to make a yarn package of cheese or cone shape.

Generally, in the spinning operation of the abovementioned open-end spinning machine, the yarn piecing method and its apparatus have been considered as important factors to attain the favorable results practically. During the open-end spinning operation, a yarn from the spinning rotor is sometimes broken. In such a case, the terminal end of a yarn from a package is fed back into the spinning rotor so as to contact the end with the above-mentioned fiber accumulation in the rotor for carrying out the piecing operation. Several feed back methods have been disclosed in prior publications. Further, at the time of starting the spinning operation of the above-mentioned open-end spinning machine, the above-mentioned feed back of the yarn into the spinning rotor has been employed as a practical method. In the piecing operation, it is required to feed back the yarn end to the fiber accumulation in the correct length and at the correct instant and correct velocity so that the piecing operation successfully takes place at the fiber accumulation surface. However, there is a frequent possibility of producing yarn defects by this piecing operation and therefore, in the practical yarn producing operation utilizing the open-end spinning machine, the rewinding operation for removing these yarn defects is still utilized.

The principal object of the present invention is to eliminate the above-mentioned drawbacks of the openend spinning.

Therefore, it is the substantial object of the present invention is to provide practical automatic piecing and knotting method and apparatus for open-end spinning machine.

In the apparatus of the present invention, when a yarn brake is detected in a certain spinning unit, the above-mentioned yarn piecing operation is firstly carried out and thereafter the yarn portion corresponding to the yarn piecing is positively taken-off by applying a knotting operation of yarn.

There are two ways of carrying out the operation of the present invention. One way is to carry out the second operation for removing yarn defects just after completion of the conventional yarn piecing operation, the other is to carry out the second operation for removing yarn defects just after completion of the yarn piecing operation by utilizing a supplementary yarn for carrying out the yarn piecing operation. In both cases, the yarn piecing and knotting apparatus is mounted on the machine frame in a movable condition along the lengthwise direction of the open-end spinning machine, and when a yarn break is detected at a certain spinning unit, the yarn piecing and knotting apparatus is moved to a working position in front of the spinning unit so as to carry out the yarn piecing and knotting operation.

One of the most characteristic features of the apparatus according to the present invention is the positive removing of yarn defects just after completion of the yarn piecing operation so that feeding the yarn defects created by the yarn piecing operation into a yarn package of the open-end spinning machine can be preferably prevented. For the convenience of easy understanding the present invention, the functions of the apparatus according to the present invention is herinafter summarized.

1. When a yarn breakage in a certain spinning unit is detected, the apparatus of the present invention takes up its working position in order to carry out the piecing and knotting operation.

2. As already explained, there are two ways for carrying out the piecing operation. One is the conventional way, that is, the means for delivering yarn from the spinning rotor and means for winding the yarn so as to produce cheese or cone are stopped, and then a certain length of yarn is rewound from the package so as to feed back the terminal end of yarn into the fiber accumulation surface of the spinning rotor, while feeding the liberated fibers into the spinning rotor. To carry out this feeding back of the terminal end of yarn into the spinning rotor, certain feeding back yarn systems, for example, a reserve system of yarn in a yarn path between the spinning rotor and the winding mechanism, have been disclosed. In any feeding back yarn system, there are frequent possibilities of creating a yarn defect which must be removed from the yarn package during the successive rewinding operation. In the present invention, the portion of yarn containing the piecing operation is positively removed in the yarn path between the spinning rotor and the winding mechanism. To attain this end, an additional means, such as a yarnknotter, is utilized. Such that after completion of the abovementioned piecing operation and before commencing the winding operation of the yarn delivered from the spinning rotor, the portion of the piecing operation is positively led to the yarn knotter so that normal yarn portions, which are connected to the yarn package and the yarn delivered from the spinning rotor respectively, are knotted and the yarn portion containing the piecing operation is positively cut-off. Thereafter, the knotted yarn is released from the knotter and the normal winding operation is simultaneously recomrnenced.

3. In a different way for carrying out the yarn piecing operation, a bobbin for supplying a supplementary yarn is used. In the operation, when the yarn breakage is detected, means for taking up the yarn from the spinning rotor and winding means are stopped, and a supplementary yarn having a certain length is simultaneously fed into the spinning rotor so as to make contact with the accumulated fibers in the spinning rotor while feeding the liberated fibers into the spinning rotor, and after completion of the yarn piecing operation, the supplementary yarn which connects to a normal yarn from the spinning rotor is led to a yarn knotter mounted on the apparatus adjacent to the yarn path between the spinning rotor and the take-up roller, while a certain length of yarn is rewound from the yarn package so as to lead to the yarn knotter, consequently, both yarns led to the knotter are knotted and a yarn portion containing the yarn piecing operation is positively cut-out. Thereafter,

the knotted yarn is released from the knotter and the normal winding operation is recommenced. To satisfactorily carry out this operation, a suction means for holding the yarn portion containing the yarn piecing operation during the knotting operation is effectively utilized.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. 1 is a perspective view of an embodiment of the present invention, showing main mechanisms,

FIG. 2 is an explanatory side view of an open-end spinning unit in a condition facing the apparatus shown in FIG. 1,

FIG. 3 is an explanatory side view of an open-end spinning unit in an operating condition of the apparatus according to the present invention,

FIG. 4 is a perspective view of a device for feeding a supplementary yarn into a spinning rotor when a yarn breakage is detected,

FIG. 5 is a plan view of the device shown in FIG. 4 but some parts removed,

FIG. 6 is a sectional view of the device, taken along line VI-VI in FIG. 5 so as to show its mechanism,

FIG. 7 is a plan view of a device for holding a supplementary yarn according to the present invention,

FIG. 8 is a sectional view of the device shown in FIG. 7, taken along line VIIIVIII in FIG. 7 so as to show its mechanism,

FIG. 9 is a perspective view of yarn suction means and cutting means, according to the present invention,

FIGS. 10 and 11 are perspective views showing relative arrangement of elements for automatic threading according to the apparatus shown in FIG. 1, respectively,

FIGS. 12 and 13 are explanatory perspective views of yarn guiding means and knotter adapted to the apparatus shown in FIG. 1,

FIGS. 14(I), (II), (III), (IV), (V), (VI), (VII) are schematic side views of the main elements of the apparatus shown in FIG. 1 for illustrating the motion thereof,

FIGS. 15a and 15b is a diagram showing timing charts of essential elements of the apparatus shown in FIG. 1 whereby motions of these elements are disclosed in relation to each other,

FIG. 16 is an explanatory side view of an open-end spinning unit in a condition facing the apparatus wherein a supplementary yarn for yarn piecing operation is omitted, according to the present invention,

FIG. 17 is a perspective view of a transfer means utilized for the apparatus shown in FIG. 16,

FIG. 18 is a plan view of a yarn holding means utilized for the apparatus shown in FIG. 16,

FIG. 19 is a sectional view of the yarn holding means, taken along line XVIIXVII, in FIG. 18,

FIG. 20 is a perspective view of an element of the apparatus shown in FIG. 16, corresponding to the element shown in FIG. 4.

DETAILED DESCRIPTION As already illustrated, the present invention can be preferably applied for carrying out the yarn piecing operation of two different types, that is, the yarn piecing operation utilizing a supplementary yarn, or the conventional yarn piecing operation of the open-end spinning system. Therefore, the mechanism of the apparatus and its function are hereinafter illustrated in detail in connection with two embodiments which represent the above-mentioned two different types of yarn piecing systems.

Referring to FIGS. 1 15, an embodiment utilizing a supplementary yarn for carrying out the yarn piecing operation is illustrated in detail. In this embodiment, a device for piecing a supplementary yarn with a bundle of fibers formed upon an accumulation surface of the spinning rotor, a mechanism for rewinding a certain length of yarn from a package of a spinning unit, a device for knotting a normal yarn portion taken from the spinning rotor right after the above-mentioned piecing operation, with the yarn portion rewound from the package, forms the main mechanism of the apparatus of the first embodiment, and several additional devices such as a device for detecting an occurrence of yarn breakage, a mechanism for stopping the apparatus at the correct working position in front of the spinning unit, and a mechanism for confirming the completion of the knotting operation etc. are mounted on the apparatus of the first embodiment. As the above-mentioned additional devices or mechanisms are disclosed in US. Pat. No. 3,540,200, Swiss Pat. No. 482,850, British Pat. NO. 1,186,946, and French Pat. No. 1,576,278, the detailed illustration of these devices is omitted in this specification.

For easy understanding of the mechanism of the first embodiment according to the present invention, the function of this embodiment is generally hereinafter described.

When a spinning yarn is broken in a spinning unit of an open-end spinning frame 200, delivery of yarn from yarn delivering aperture 204 of a spinning rotor 203 is stopped so that a pair of take-up rollers 206 and 207 take up without slack a yarn from the spinning rotor 203. In this condition, a feeler 209, which is mounted on each spinning unit, is in a working position so that an actuator (not shown) is energized. When the actuator is energized, supply of the liberated fibers into the spinning rotor, and winding motion for making a yarn package are stopped.

A carrier of the yarn piecing and knotting apparatus is mounted on a guide rail (not shown) disposed on the open-end spinning frame in such a way that the carrier 160 can be displaced along the lengthwise direction of the spinning frame 200 adjacent to, in front of, and facing each spinning unit. A plurality of brackets for supporting component devices of the apparatus are secured to rear side wall 161, side walls 162 and 163 of the carrier 160. The carrier 160 is provided with a device for detecting yarn break of any spinning units of the open-end spinning frame. The carrier 160 is also provided with an automatic positioning mechanism which is actuated by an output signal of the abovementioned detecting device. The detecting device and positioning device are illustrated in the abovementioned patents in detail therefore, further illustration of the mechanisms of these devices are omitted.

When the detecting device (not shown) mounted on the carrier 160 detects a yarn break during the travelling motion of the carrier 160 along the lengthwise direction of the open-end spinning frame, the positioning device (not shown) is actuated so that the carrier 160 is stopped at its working position.

When the carrier 160 is positioned at its correct working position, a device for holding a supplementary yarn (hereinafter referred to as holding device) holds an end of the supplementary yarn and leads the end of yarn to a position right below the spinning rotor, where a suction air current flows into the delivery aperture.

When the holding of the yarn end by the holding device is released, the above-mentioned end of yarn is sucked into the delivery aperture of the spinning rotor by the above-mentioned suction air current. A yarn reserve device is disposed between the holding device and the device for feeding the supplementary yarn (hereinafter referred to as the feeding mechanism). Before feeding the yarn end into the delivery aperture of the spinning rotor, a certain lengthof supplementary yarn is reserved in the yarn reserve device so as to eliminate any resistance to the above-mentioned feeding of the end of the supplementary yarn into the spinning rotor and to allow the feeding of the above-mentioned yarn end until the yarn end reaches to an effective zone of centrifugal force created by the high speed rotation of the spinning rotor.

Next, the supply of the liberated fibers into the spinning rotor and motion of the take-up rollers are restarted simultaneously in order to complete the piecing of the end of supplementary yarn with a bundle of f1- bers accumulated on the accumulation surface of the spinning rotor. When the motion of the take-up roller is commenced the supplementary yarn is cut at the above-mentioned reserve device and one of the cut ends is led to a first suction means so as to take-up the yarn delivered from the take-up rollers. The yarn taken-up by the first suction means is hereinafter referred to as an upstream yarn.

At the same time as the above-mentioned operation, a yarn package is rewound by a rewound mechanism so that a broken yarn end is retrieved by a second suction means mounted on the carrier 160. Next, the retrieved yarn end is led to a position for carrying out a knotting operation. The yarn rewound from the package and carried to the position for the knotting operation is hereinafter referred to as a downstream yarn.

When the upstream and downstream yarns are led to the position for the knotting operation, the knotter, which is mounted on the carrier 160, is actuated so that the knotting operation is carried out, and excess portions of the upstream and downstream yarns are cut and removed, then the knotted portion of yarn is released from the knotter so that the normal spinning operation is recommenced. In the above-mentioned steps of operation, motions of the component devices or mechanisms are automatically controlled by a programing cam mechanism driven by a motor. The programing cam mechanism is designed so as to complete the above-mentioned steps in one revolution of the shaft of the motor.

Device for piecing a supplementary yarn.

In the present embodiment, a device for piecing a supplementary yarn with a bundle of fibers accumulated upon an accumulation surface of the spinning rotor 203 comprises a supply mechanism 1 for supplying a supplementary yarn and a holding device 21 for holding an end of the supplementary yarn and for leading the end of the yarn to a position right below the spinning rotor 203, a feeler control device 50 and a first suction means S, for taking the upstream yarn.

An unwinding mechanism for taking up a certain length of yarn from a yarn package comprising a device for supporting a foot pedal and means for turning the yarn package in the unwinding direction, a second suction means for taking the yarn end therein. In the attached drawings, the above-mentioned three elements are represented by numerals 141., 123 and a letter S respectively. A knotting device mounted on the carrier 160 comprises a pair of guide wire 106 and 108 and a knotter 75.

As shown particularly in FIG. 2, the holding device 21 is closely positioned upon the supply mechanism 1 in a waiting condition so that the supplementary yarn 401 from a cheese 400 passes through the holding device 21 and the supply mechanism 1 and an upper end of the yarn 402 is projected beyond the upper surface of the holding device 21.

The supply mechanism 1 is provided with a feed roller 2 and a driven roller 3, the feed roller 2 is driven by a motor M directly. The driven roller 3 is rotatably supported by a roller bracket 5 in such a way that, when it is required to supply the supplementary yarn, the roller 3 is driven by the frictional contact with the feed roller 2 and vice versa. The roller bracket 5 is supported by a shaft 6 and is provided with a bracket arm 7. When the tip portion of the bracket arm 7 is pulled toward the W direction in FIG. 6, the engagement of the roller 3 with the feed roller 2 is released. Consequently, even though the feed roller 2 is rotated from the inertia of the motor M excess feeding of the supplementary yarn can be prevented. The supply mechanism 1 is provided with a thread passage 9 for leading the supplementary yarn to a position adjacently above a nip point between the feed roller 2 and the driven roller 3. The supply mechanism 1 is also provided with a conical slit 10 which connects a conduit 11 connected to a supply source of compressed air with the passage 9 so that a strong air stream flows upward. A hook wire 15 is mounted on the supply mechanism 1 at a side position of the thread passage 9. The hook wire 15 functions to transfer the supplementary yarn to the knotter after the supplementary yarn is: sucked into the first suction means S whereupon the yarn piecing operation of the supplementary yarn with the bundle of fibers accumulated upon the accumulation surface of the spinning rotor 203 is completed. The above-mentioned supply mechanism 1 is supported by a guide rod 12, and can be displaced'toward an inclined lower position by means of a rack bar 13.

Referring to FIG. 8, the holding device 21 is provided with a slit 22 having a C shape lateral cross section. The slit 22 is provided with a longitudinal split groove 25. A nip piece 28 is continuously urged towards the nip surface 27 of the thread passage 23 by means of a spring 29. An L-shaped lever 31 is connected to a rod 30 of the nip piece 28 so as to release the engagement of the nip piece 28 with the nip surface 27 by pulling the rod 30 outwards. This motion of the rod 30 is attained by pulling the L-shaped lever 31 toward the W, direction in FIG. 7. A conical slit 24 is formed around the slit 22 so that the conduit 26 is connected to the slit 22 and an air flow in the upward direction can be created in the slit 22 by supplying compressed air via the conduit 26. Therefore, the supplementary yarn can be carried upward through the slit 22. The holding device 21 is slidably engaged with a dovetail groove 39 in the support member 35 and displaced forward or backward by the rack 37. A plate spring 38 is mounted on the holding device 21 so as to urge to the support member 35. Consequently, the holding device 21 is always urged to slide toward the right hand direction (in FIG. 7) in the dovetail groove 39. As the holding device 21 is supported by the support member 35 as mentioned above, when the holding device 21 is displaced forward, a side 34 of the holding device 21 contacts a stopper 211, which is shown by a dash line in FIG. 7, mounted on the spinning unit, so that the holding device 21 is stopped at the correct working position where the delivery aperture 204 of the spinning rotor 203 is superposed above the thread passage 23 of the holding device 21.

Referring to FIGS. 1, 2 and 3, guide rods 12 and 36, racks 37 and 13 are slidably supported by a bracket 45 secured to the rear side wall of the carrier 160 so that the holding device 21 and the supply mechanism 1 can be slidably moved along a pair of passages which are symmetrically inclined to the passage of the spinning yarn. Further, a pair of pinions 40, 14 are secured on a shaft which is rotatably mounted upon the bracket 45 so that these pinions are engaged with the rack 37 and 13 respectively. The pinion 40 is engaged with a wheel 42 of a reversible motor M by way of an intermediate wheel 41. The reversible motor M is secured to the carrier 160 by means of a bracket 46. Therefore, the holding device 21 and the supply mechanism 1 can be displaced forward and backward.

As already illustrated, in the present embodiment, the end of supplementary yarn is fed into the delivery aperture 204 of the spinning rotor 203 so as to connect it with a bundle of fibers accumulated upon the accumulation surface of the spinning rotor 203 in the reverse direction to that of the normal running of spun yarn. It is important that a length of the supplementary yarn sufficient to lead the end of yarn into an active zone of centrifugal force is required to carry-out the desirable piecing operation. To attain this end, a yarn reserve device 150 and a feeler stopper 50 to actuate a limit switch (not shown) are mounted on the carrier 160. The yarn reserve device 150 functions to reserve a certain length of the supplementary yarn to feed the above-mentioned sufficient length of the supplementary yarn into the spinning rotor 203. The yarn reserve device 150 is turnably supported on the carrier 160, the device 150 is provided with a lever 151 which engages a hook 51 of a feeler stopper 50, and is also provided with a rod 152 for holding and releasing the supplementary yarn. The lever and rod are capable of turning counterclockwise (in FIGS. and 11) by means of the helical spring 153. (Referring to FIG. 1) A feeler control device is mounted on a slide 52. A connecting lever 53 connects a lever 54 secured to the shaft of a motor M, with a slide 52 slidably mounted on a guide rod 56 supported by a bracket 57 secured to a carrier 160. Therefore, the slide 52 is capable of sliding in right or left hand directions (in FIG. 1). An L-shaped hook 51 is mounted on the feeler control device. Therefore, when the hook 51 engages the yarn reserve device 150 and the feeler control device is displaced forward, the holding of the supplementary yarn is suddenly released and a feeler 209 is simultaneously held so that the limit switch is actuated. Further, at the tip of the lever 54, a magnetic switch (not shown) is mounted so that when the slide 52 is displaced to rearward direction, the slide 52 contacts therewith so as to stop the rotation of the motor M at each single rotation thereof.

Referring to FIGS. 1, 2, 3, 9, an upstream yarn takeup device comprises a first suction means 8, for sucking the supplementary yarn after completion of the yarn piecing operation and a pair of scissors 63. This device is mounted on a rack which engages a pinion 68 by way of a wheel 69 of a motor M This device slides in either the right hand direction or left hand direction (in FIG. 1) according to the motion of the motor M This slide motion is guided by a guide rod secured to a bracket 66 mounted on the carrier 160.

The above-mentioned devices for piecing the supplementary yarn with a bundle of fibers accumulated on the accumulation surface of the spinning rotor 203 operate as follows:

Referring to FIGS. 14, 15a and 15b, when the carrier 160 of the apparatus is positioned at its working position correctly facing a spinning unit wherein a spinning yarn is broken, the motor M is simultaneously turned to the normal direction so that the engagement of the rollers 2 and 3 of the supply mechanism 1 is released and the holding device 21 is displaced forward while holding an end of the supplementary yarn 401 from a supplementary cone 400. This condition is shown in FIG. 14(I), and represented by (I) in FIG. 15.

During the above-mentioned forward motion of the holding device 21, the supplementary yarn is hooked by a rod 152 of the yarn reserve device as shown in FIG. 14(II) and a certain length of supplementary yarn is reserved in a biased yarn path. And when the holding device 21 contacts the stopper 211 mounted on the spinning unit, the thread passage 23 of the holding device 21 comes to a position right below the delivery aperture 204 of the spinning rotor 203, as shown in FIG. 14(II) and represented by (II) in FIG. 15.

When jet air is fed from the conduit 26, the end of the supplementary yarn, which is held by the nip piece 28 and laid on the upper surface of the holding device 21 is caught by the jet air stream directed upwards. This end of the yarn is represented by 402. Next, the nip piece 28 is displaced so as to release the supplementary yarn from being held and the rollers 2 and 3 are turned slightly so as to carry the end of the supplementary yarn to the delivery aperture 204 of the spinning rotor 203. Consequently, the end of the supplementary yarn is fed to a position where the suction air stream of the spinning rotor 203 takes effect such suction air stream of the spinning rotor may be the result of either the low pressure generated by the spinning rotor itself or an air stream supplied into the delivery aperture from the outside, such as through the air supply pipe 205. Then the supply of the supplementary yarn and ejection of the jet air are stopped. In this condition, the end portion of the supplementary yarn is caught by the suction air stream of the spinning rotor 203.

As mentioned above, a strong jet air is utilized for carrying the end portion 402 of the supplementary yarn into the delivery aperture 204, thus there are no troubles with the insertion of the supplementary yarn into the delivery aperture 204.

Next, the motor M is driven so that the feeler stopper 50 is displaced forward, consequently the rod 152 of the yarn reserve device which engages with the supplementary yarn by urging the helical spring 153 is taken away from the yarn. The above-mentioned conditions are represented by FIG. 14(II) and FIG. 14(III) or FIG. 10 and FIG. 11 respectively. Therefore, the supplementary yarn 404 is released from the biased passage and guided by a yarn guide 208 so that the reserved length of the supplementary yarn is led into an inside position of the spinning rotor 203 where the centrifugal force takes effect. The feeler stopper 50 simultaneously pushes the feeler 209, thereby a magnet switch (not shown) is actuated so that supply of the liberated fibers into the spinning rotor 203 and the normal rotation of the rollers 206 and 207 is commenced so as to take-up the upstream yarn 404. It is possible to omit the above-mentioned feeler holder without any trouble in carrying out the above-mentioned operation, however, it is preferable to utilize the feeler holder to ensure perfect operation. The above-mentioned condition is shown in FIG. 14(III) and represented by (III) in FIG. 15. In this operation, the motor M continues its rotation after the feeler device holds the feeler 209 and stops after returning to its original position.

The motor M commences to drive simultaneously with the motion of the motor M and the first suction means S is displaced to a position above the supply mechanism 1 as shown in FIG. 14(Ill). When the supplementary yarn 404i is taken-up from the delivery aperture 204! of the spinning rotor after completion of the yarn piecing operation, the scissors 63 are actuated to cut the supplementary yarn 404, consequently the upstream yarn, which is being delivered from the delivery aperture 204 is sucked into the first suction means 8,.

By rotating the motor M reversely so as to move the first suction means S backward, the upstream yarn 405 is carried along a predetermined yarn passage defined by the hook 15 of the supply mechanism 1 and the passage of the first suction means S This upstream yarn 405 is then knotted with the downstream yarn unwound from the package (cheese or cone) by the knotter 75. After completion of the knotting operation, the motor M is rotated in the reverse direction so that the supply mechanism 1 and the holding device 21 are displaced to their original waiting position. When the supply mechanism 1 is displaced to its original waiting position, the supplementary yarn is held by the rollers 2 and 3, and the motor M is turned so as to feed a predetermined length of the supplementary yarn to the holding device 21 by utilizing a jet air stream and the supplementary yarn is held by the nip piece 28 as shown in FIG. 14( VII), and as represented by (VII) in FIG. 15.

As already illustrated, in the present embodiment, it is required to unwind a yarn from a package when the knotting operation is carried out. In this embodiment, when the detector (not shown) mounted on the apparatus detects a yarn breakage in a certain spinning unit, the contact of the package 302 with the driving drum 300 is released, next a separate drive means 121 is caused to contact the package so as to unwind yarn therefrom, a second suction means is caused to contact the package so as to retrieve the broken end of yarn (downstream yarn). And after completion of the knotting operation, of the downstream yarn with the upstream yarn, the package 302 is again caused to contact the drive drum 300 so as to restart the normal winding operation.

As shown in FIGS. 2 and 3, a package bobbin 302 is rotatably supported by a pair of cradle arms 304 which are turnably supported by a cradle shaft 305 supported by the spinning unit in such a way that the cradle shaft 305 is arranged parallel to the drum-shaft 301 which is driven positively by a driving mechanism (not shown). The cradle arm 304 is connected to a foot lever 306 by a connecting arm 30612 and is always energized so as to turn upward about a shaft 305. Consequently, the package bobbin 302 is always urged towards the driving drum 300.

When the carrier 160 of the present apparatus is stopped at the correct working position, an air cylinder C which is mounted on the carrier 160 and actuated by an output signal of the detector, pushes a piston rod 140, thereby the foot lever presser 14] disposed below the tip of the piston rod is pushed downward so that the foot step 307 of the foot lever 306 is pushed downward. Consequently, the package 302 is released from contact with the drive drum 300. Referring to FIG. 3, in this released position, the package 302, which is positively driven by the drive drum 300, is capable of free rotation. A rotary actuator A is mounted on a bracket 126 secured to the carrier 160, and a rotary arm 123 is mounted on its shaft. A variable speed reversible motor M is mounted on the tip of the arm 123, and a reversible roller 121 is coaxially mounted upon the arm 123 in such a way that the roller 121 contacts the package 302 so as to rotate it in the unwinding direction. And when the action of the actuator A is stopped by means of contacting the roller 12] with the package 302. The arm 123 is provided with a specially designed cam surface 124 by which the aperture of the second suction means S is positioned at a predetermined distance from the package 302 for any size of the package 302 when the roller 121 contacts with the package 302. The second suction means S is turnably supported by a rotary actuator A secured to the side wall 162 of the carrier 160. In FIG. 1, F designated a suction pipe which is connected to a suction source (not shown), and also connected to the second suction means S The second suction means S is provided with a slit (not shown) formed at its tip. The width of the slit extends along the whole width of the package 302. A projection 132 is formed at an intermediate side of the suction means S1 so that the excess turning of the suction means S is restricted by contacting with the cam surface 124 formed at the upper surface of the roller arm 123. Consequently, the slit of the suction means S can be brought to the winding surface of the package 302 at a predetermined distance irrespective of the variation of package size.

When the carrier stops at the correct working position facing a spinning unit where a spinning yarn is broken, the air cylinder C is displaced forward so that the foot lever 306 is pushed downward, consequently the yarn package 302 is parted from the drive drum 300. Next, the rotary actuator A is actuated so that the arm 123 is turned in a clockwise direction and the roller 121 contacts with the package 302. Next the rotary actuator A is actuated so that the suction means S is turned counterclockwise. At this moment, the projection 132 contacts the cam surface 124 of the arm 123 so that the turning motion of the suction means S is restricted. The above-mentioned conditions are shown in FIG. 14(I) and FIG. 14(II).

In the condition shown in FIG. 140]), when the roller 121 is turned in the unwinding direction and the second suction means S is simultaneously actuated, the yarn package 302 is unwound so that the retrieved yarn is sucked into the suction means S Then, the rotary actuator A is actuated to turn in the reverse direction, so that the second suction means S5 is turned to its original waiting position. Consequently, the yarn from the yarn package 302, that is, the downstream yarn is extended between the yarn package 302 and the second suction means S When a predetermined length of the downstream yarn is sucked into the second suction means S the rotation of the roller 121 is stopped. As mentioned above, the slit of the second suction means S can be positioned at a predetermined distance from the winding surface of the package 302 when retrieving a broken end of yarn from the winding surface of the package 302. Therefore, the abovementioned retrieving motion and the unwinding motion can be carried out perfectly. And after completion of the unwinding motion of the downstream yarn 310, the upstream yarn 405 and downstream yarn 310 are knotted to each other by the knotter 75.

Before carrying out the knotting operation, it is required ot lead the downstream yarn 310 extended between the yarn package to and the second suction means S to a suitable position for carrying out the knotting operation. To lead the downstream yarn 310, a pair of guide wires 106 and 108 are rigidly mounted on a shaft 105 at a predetermined intervened distance, and the shaft 105 is pivoted to a bracket 102 secured to the rear side wall 161 of the carrier 160. As shown in FIGS. 12 and 13, the guide wires 106 and 108 ar eprovided with recess portions 107 and 109 respectively. These recess portions 107 and 109 are positioned below the downstream yarn 310. A cam arm 104 is rigidly mounted on an end portion of the shaft 105, and the cam arm 104 is provided with a cam roll 103 at the tip thereof. The guide wires 106 and 108, the shaft 105 and the cam arm 104 form a guide device for leading the downstream yarn 310. When the knotter 75 is displaced forward (from right to left in FIGS. 12 and 13), the front end of a cam plate 98 rigidly supported by the knotter 75 contacts the cam roller 103 and urges the roller 103, so that the shaft 105 is turned clockwise. By this turning motion of the shaft 105, the guide wires 106 and 108 are turned clockwise while supporting the downstream yarn 310, as shown in FIG. 13, and when the cam roller 103rides on the upper surface 99 of the cam plate 98, the turning motion of the guide wires 106 and 108 is terminated. Therefore, as shown in FIG. 14(IV), the downstream yarn 310 is positioned partly between the second suction means S and the guide wire 106, partly between the guide wires 106 and 108, and partly between the guide wire 108 and the package 302. The downstream yarn between the guide wires 106 and 108 is represented by the numeral 311. As shown in FIG. 13, the downstream yarn 311 is positioned adjacent to the upstream yarn 405 and parallel to it, consequently, the preparation for carrying out the knotting operation are completed.

The mechanism and function of the knotter 75 is hereinafter illustrated in detail. Referring to FIG. 1, the knotter 75 is provided with a driving means comprising a motor M and a gear train composed of gears 81, 82, 83, 84, 85, 86 and 87. An arm 88 is secured to the gear 87 so that the arm 88 is turned with gear 87. A rod 90 is pivotally supported at its one end on the arm 88 by a pin 89 and is pivoted at its other end on a bracket 91 secured to the side wall 163, consequently, a crank mechanism is formed by the rod 90 and the arm 88. The gear 84 actuates the knotter 75 by way of the gear 83. However, by the action of a spring 96 mounted on the knotter 75, a stopper 95 is urged in the counterclockwise direction so that the gear 84 is maintained at rest, in other words, the knotter 75 is at rest. An L- shaped stripper releasing member 93 is also mounted on the knotter frame 76, and when the knotter is displaced forward to its working position, a releasing pin 92 mounted on the gear works the releasing member 93 so that the stopper is released for carrying out the operation of the knotter 75.

The knotter 75 is displaced forward or backward along a predetermined passage define by the guide rod 78 which is connected to the guide angle 79 and secured to the side wall 163, for carrying out the knotting operation.

A third suction means S is disposed on a tip of the piston rod of an air-cyhnder Cg which is mounted on the side wall 162. A wire net 72 is disposed in a suction aperture of the third suction means S consequently the excess portions of the upstream yarn 405 and downstream yarn 311 after completion of the knotting operation can be reserved upon the wire net 72 by air suction force of a pipe 33. Therefore, the yarn portions adjacent to the knotter 75 are tensioned.

To clarify the above-mentioned functions of the knotter 75 and its related elements, the operations of these members are hereinafter summarized.

After completion of the yarn piecing operation, the upstream yarn 405 is sucked into the first suction means S and the downstream yarn 310 is retrieved and unwound from the yarn package 302 by means of the second suction means S '(FIG. 14(IV)), the motor M is actuated so that the gear 87 is rotated through the gears 81, 82, 85 and 86. As the arm 88 is connected to the rod 90, when the motor M is actuated, the knotter 75 is displaced forward along a predetermined passage defined by the guide rod 78 and the guide angle 79. The cam plate 98 is also displaced forward in accordance with the forward motion of the knotter 75 so that the cam plate 98 engages the cam roller 103. By this engagement, the guide wires 106 and 108 are turned upward about thereby a portion 311 of the downstream yarn 310 is displaced to a position adjacent to the above-mentioned upstream yarn 40S and in parallel with it as shown in FIGS. 13 and 14(IV). When the knotter 75 reaches the terminal position of its forward displacement, the pin 92 disposed on the gear 85 turns the stripper releasing member 93 so that the stopper 95 is pushed while compressing the spring 96. Consequently, the brake between the knotter 75 and its drive mechanism composed of the above-mentioned gear train is released and the knotter 75 is actuated to carry out its knotting operation and the excess portions of the upstream yarn 405 and the downstream yarn 311 are cut-off.

After completion of the above-mentioned knotting operation, the knotter 75 is displaced backward to its original waiting position. By this backward motion of the knotter 75, the guide wires 106 and 108 are turned to their original waiting positions shown in FIG. 12. And when the knotter 75 arrives at its original waiting position, the rotation of the motor M is stopped. As mentioned above, the knotting operation is carried out at a position biased from the normal yarn passage for carrying out the spinning operation. As the downstream yarn 405 is continuously delivered from the spinning rotor 203, during the knotting operation, it is necessary to prevent loosening of the upstream yarn 405. Therefore, the air cylinder C of the third suction means S is displaced forward according to the forward motion of the knotter 75 so as to suck the excess portion of the upstream yarn 405 from the time of the yarn knotting operation, and the motor M is simultaneously rotated to wind the above-mentioned reserved yarn upon the yarn package 302 with higher speed (FIG. 14(VI)). To prevent yarn breakage during the winding operation by the motor M the motor M is stopped just before exhaustion of the reserved yarn, and then the rotary actuator A is turned in the reverse direction (counterclockwise) at the time when the motor M is stopped. Therefore, the cylinder C is receded so as to contact the yarn package 302 with the drive drum 300. After completion of these operations, the air cylinder C is receded and one cycle of the yarn piecing and knotting operation is completed (FIG. 14(VII)). In the drawing of FIG. 15, the relative motion between the de vices or elements of the apparatus may be understood by reference to the figure number of FIG. 14.

By applying the knotting operation after the yarn piecing operation, any yarn defects created by the yarn piecing operation can be completely removed from the yarn package.

Referring to FIGS. 16-20, mechanism and function of the second embodiment according to the present invention are hereinafter illustrated. As already illustrated, in the second embodiment, the conventional yarn piecing mechanism can be employed. Therefore, the winding mechanism and its function only are illustrated in detail. For the convenience of easy understanding, elements having the same function as in the first embodiment are represented by the same numerals. In this second embodiment, yarn transferring mechanism 500 transfer the downstream yarn to the supply mechanism 1a. The supply mechanism 1a transfers an end of the downstream yarn to a position right below the holding device 21. A swing arm 503 is mounted on a shaft 502 of a rotary actuator A rigidly supported by the rear side wall 161 of the apparatus. In the yarn transfer mechanism, a guide bar 504 provided with a V-shaped guide portion 505 is mounted on the tip of the swing arm 503, an auxiliary rotary actuator A is mounted at the middle portion of the swing arm 503 and a second swing arm 506 is secured to the auxiliary rotary actuator A The second swing arm 506 is also provided with a guide bar 508 having a V-shaped guide portion 507. The holding device 21 is provided with a slit 25 connected to a thread passage 23, and a guide 509 having a V-shaped cross section is formed in front of the slit 25 so that the downstream yarn can be easily fed into the slit 25. A stational knife 510 is rigidly mounted on the upper surface of the holding device 21, and a scissor 512 is turnably supported by a pin 511 mounted on the knife 510 in such a way that the scissor 512 is normally opened from the knife 510 by a force created by a helical spring 513 as shown in FIG. 18. A rod is connected to an end of the scissor 512 and the rod is passed through the spring 513 as shown in FIG. 18. Therefore, when the rod is pulled toward the W direction, the scissor 512 is turned about the pin 511 so that the opening between the knife 510 and the scissor 512 is closed, thereby the downstream yarn above the thread passage 23 is cut.

The supply mechanism 1a is provided with a guide groove 515 which is connected to a guide groove 514 having a V-shaped cross-section. These grooves 514 and 515 are formed so as to lead the downstream yarn into the mechanism 1a. The rollers 2 and 3 are mounted in such a way that the nip line of these rollers 2 and 3 is parallel to the guide groove 515 and the groove 515 extends to these rollers 2 and 3. Therefore, the above-mentioned arrangement shows phase difference from the first embodiment shown in FIG. 4. Further, as it is not required to transfer the downstream yarn from the supply mechanism lla to the holding device 21, means for creating jet air can be omitted.

Further, as the downstream yarn can be utilized for carrying out the piecing operation, the scissor 63, 64 for cutting the supplementary yarn and yarn guide wires 106 and 108 are omitted. However, other elements of the supply mechanism 1a and the holding device 21 of the first embodiment can be similarly utilized in the second embodiment.

As shown in FIG. 16, the yarn transfer mechanism 500 is provided with the rotary actuator A, which turns to the left and the auxiliary rotary actuator A which turns to the right, and the swing arms 503 and 506 are positioned in front of the spinning unit wherein a spinning yarn is broken in a V-shaped open condition like Y shape. In a similar way as in the first embodiment, the second suction means S is actuated to retrieve the broken end of yarn from the package 302 and the retrieved yarn is sucked into the second suction means 8,. The downstream yarn 310, which extends from the package 302 to the second suction means S is positioned above the guide portion 505 of the swing arm 503. When the rotary actuator A is actuated to turn to the right (FIG. 16), the downstream yarn 310 is taken-up from the second suction means S and is led by the guide portion 505, consequently, the downstream yarn 310 is carried to the terminal of its swing motion toward the right hand side while passing over the hold ing device 21 and the supply mechanism la. Next, when the actuator A is turned to the left, the downstream yarn 310 is hung on to the guide portion 507 of the guide bar 508, consequently, the downstream yarn 310 is led into the thread passage 523 of the holding device 21 and the guide groove 515 of the supply mechanism la. When the actuator A turns to the left, a magnet pulling the rod toward the W, direction is deenergized simultaneously with the termination of the above-mentioned'turning of the actuator A so that the downstream yarn is held by the holding device. 21. Next, the scissor 512 is actuated by pulling the rod toward the W direction (FIG. 18)) so that the downstream yarn 310 is cut. The cut-out1 yarn piece is sucked into the second suction means S and the end of the downstream yarn is held by the holding device 21 and the supply mechanism 1a. This condition corresponds to the condition shown in FIG. 14(I) wherein the supplementary yarn 401 is held. When the end of the downstream yarn is held by the holding device 21, the rotary actuator A turns clockwise so that the swing arm 506 is returned'to its original waiting position. The end of downstream yarn held by the holding device 21 is fed into the delivery aperture .204 of the spinning rotor 203 in a similar manner as in the first embodiment, and after completion of the yarn piecing operation in the spinning rotor 203, the downstream yarn 302 is sucked into the first suction means S,. By applying the above-mentioned sucking operation, the upstream yarn coming from the delivery aperture 204 of the spinning rotor 203 is also sucked into the suction means 8,. Therefore, when the first suction means S, is displaced backwards by the reverse rotation of the motor M the upstream yarn is hung onto the guide groove 515 as shown in FIG. 14(IV). The downstream yarn 310 is also hung onto the guide groove 515, so that the upstream yarn and the downstream yarn 310 are extended along a predetermined passage in a parallel condition. Therefore, the knotting operation of these two yarns can be carried out by the knotter 75 in a similar fashion as in the first embodiment (FIG. 14(V)). After completion of the above-mentioned knotting operation, the excess yarns cut-off is sucked into the suction means S And the actuator A is turned in the reverse direction so that the yarn transfer mechanism 500 is displaced to its original waiting position.

What is claimed is:

1. In an open-end spinning process, an improved method of yarn piecing and knotting when said yarn breaks, said process including the steps of; supplying liberated fibers into a spinning rotor rotating at high speed so that said liberated fibers are continuously deposited upon a fiber accumulation surface of said spinning rotor; removing a bundle of fibers from said fiber accumulation surface; twisting said removed bundle of fibers by high speed rotation of said spinning rotor; continuously delivering a twisted yarn from a delivery aperture of said spinning rotor; forming a yarn package from said delivered yarn; wherein said improved yarn piecing and knotting includes the steps of:

preparing a predetermined reserve length of a supplementary yarn supplied from a source in a biased yarn path by means of a yarn reserve device said biased yarn path being V-shaped;

feeding said supplementary yarn into said delivery aperture in the reverse direction to that of the normal running of a spun yarn until an end of said yarn reaches a zone affected by the centrifugal force created by said high speed rotation of said spinning rotor whereby said end of yarn is pieced with said bundle of fibers;

taking up a twisted yarn from said delivery aperture of said spinning rotor so that an upstream yarn is formed;

retrieving the broken end of said yarn from said yarn package and unwinding a predetermined length of said yarn from said yarn package so that a downstream yarn is formed;

leading said downstream yarn and said upstream yarn along a predetermined passage in a parallel and close condition;

knotting both of said yarns at a position in said prede termined passage; cutting the excess length of said upstream yarn which includes a portion containing said yarn piecing, and an excess portion of said downstream yarn; and,

positioning said knotted yarn on a normal spinning yarn passage so that a normal spinning operation can be continuously carried out.

2. The improved yarn piecing and knotting method as recited in claim 1 wherein the step of feeding said supplementary yarn into said delivery aperture includes the step of:

carrying an end of said supplementary yarn by means of a jet air current into an effective zone of the suction air stream of said spinning rotor flowing into said delivery aperture.

3. The improved yarn piecing and knotting method as recited in claim 2 where the step of carrying said end of said supplementary yarn is followed by the step of:

feeding of said supplementary yarn in said reverse direction to that ofthe normal running of a spun yarn by releasing said yarn from said yarn reserve device until said end of said supplementary yarn reaches an effective zone of centrifugal force created by high speed rotation of said spinning rotor; and, simultaneously stopping said jet air current.

4. The improved yarn piecing and knotting method as recited in claim 3 where the step of stopping said jet air current is followed by the step of:

commencing the feeding of said liberated fibers into said spinning rotor; and, engaging said supplementary yarn in the nip of the rotating take-up roller when said supplementary yarn is being fed in said reverse direction.

5. The improved yarn piecing and knotting method as recited in claim 1, including the step of:

temporarily reserving a loosened yarn extending from said delivery aperture of said spinning rotor to the knotter by means of a suction device operating from the time of the knotting operation.

6. The improved yarn piecing and knotting method as recited in claim 5, including the step of:

rotating a yarn package with higher speed so as to wind the reserved yarn on said suction device.

7. An improved yarn piecing and knotting apparatus for an open-end spinning machine provided with a plurality of spinning units, each unit having a spinning rotor provided with fiber accumulation surface and a delivery aperture, driving means for rotating said spinning rotor at a high speed, means for supplying liberated fibers into said spinning rotor so that said fibers are deposited upon said accumulation surface, leading means for an upstream yarn continuously taken from said delivery aperture and for leading a downstream yarn unwound from said yarn package along a predetermined passage, a knotter for knotting both yarns at a position on said predetermined passage, take-up means for taking up a twisted yarn from said delivery aperture, winding means for producing a yarn package from said yarn taken up from said delivery aperture, where the improvement comprises:

means for reserving a predetermined length of a supplementary yarn supplied form a source and releasing it instantaneously;

jet air current means for flowing an air current in the reverse direction to that of the normal running of spun yarn into said delivery aperture of the spinning rotor;

means for feeding an end of yarn into said delivery aperture of said spinning rotor in the reverse direction to that of the normal running of a spun yarn when a spinning yarn is broken until said end reaches a zone affected by centrifugal force created by high speed rotation of said spinning rotor so that a piecing operation can be carried out.

8. The improved yarn piecing and knotting apparatus according to claim 7, wherein said means of leading an end of yarn into said delivery aperture of said spinning rotor further comprises a holding device for holding an end of said supplementary yarn, and for leading said end of said supplementary yarn into said feeding device.

9. The improved yarn piecing and knotting apparatus according to claim 8 further comprising a third suction means for temporarily reserving an excess length of 

1. In an open-end spinning process, an improved method of yarn piecing and knotting when said yarn breaks, said process including the steps of; supplying liberated fibers into a spinning rotor rotating at high speed so that said liberated fibers are continuously deposited upon a fiber accumulation surface of said spinning rotor; removing a bundle of fibers from said fiber accumulation surface; twisting said removed bundle of fibers by high speed rotation of said spinning rotor; continuously delivering a twisted yarn from a delivery aperture of said spinning rotor; forming a yarn packAge from said delivered yarn; wherein said improved yarn piecing and knotting includes the steps of: preparing a predetermined reserve length of a supplementary yarn supplied from a source in a biased yarn path by means of a yarn reserve device said biased yarn path being V-shaped; feeding said supplementary yarn into said delivery aperture in the reverse direction to that of the normal running of a spun yarn until an end of said yarn reaches a zone affected by the centrifugal force created by said high speed rotation of said spinning rotor whereby said end of yarn is pieced with said bundle of fibers; taking up a twisted yarn from said delivery aperture of said spinning rotor so that an upstream yarn is formed; retrieving the broken end of said yarn from said yarn package and unwinding a predetermined length of said yarn from said yarn package so that a downstream yarn is formed; leading said downstream yarn and said upstream yarn along a predetermined passage in a parallel and close condition; knotting both of said yarns at a position in said predetermined passage; cutting the excess length of said upstream yarn which includes a portion containing said yarn piecing, and an excess portion of said downstream yarn; and, positioning said knotted yarn on a normal spinning yarn passage so that a normal spinning operation can be continuously carried out.
 2. The improved yarn piecing and knotting method as recited in claim 1 wherein the step of feeding said supplementary yarn into said delivery aperture includes the step of: carrying an end of said supplementary yarn by means of a jet air current into an effective zone of the suction air stream of said spinning rotor flowing into said delivery aperture.
 3. The improved yarn piecing and knotting method as recited in claim 2 where the step of carrying said end of said supplementary yarn is followed by the step of: feeding of said supplementary yarn in said reverse direction to that of the normal running of a spun yarn by releasing said yarn from said yarn reserve device until said end of said supplementary yarn reaches an effective zone of centrifugal force created by high speed rotation of said spinning rotor; and, simultaneously stopping said jet air current.
 4. The improved yarn piecing and knotting method as recited in claim 3 where the step of stopping said jet air current is followed by the step of: commencing the feeding of said liberated fibers into said spinning rotor; and, engaging said supplementary yarn in the nip of the rotating take-up roller when said supplementary yarn is being fed in said reverse direction.
 5. The improved yarn piecing and knotting method as recited in claim 1, including the step of: temporarily reserving a loosened yarn extending from said delivery aperture of said spinning rotor to the knotter by means of a suction device operating from the time of the knotting operation.
 6. The improved yarn piecing and knotting method as recited in claim 5, including the step of: rotating a yarn package with higher speed so as to wind the reserved yarn on said suction device.
 7. An improved yarn piecing and knotting apparatus for an open-end spinning machine provided with a plurality of spinning units, each unit having a spinning rotor provided with fiber accumulation surface and a delivery aperture, driving means for rotating said spinning rotor at a high speed, means for supplying liberated fibers into said spinning rotor so that said fibers are deposited upon said accumulation surface, leading means for an upstream yarn continuously taken from said delivery aperture and for leading a downstream yarn unwound from said yarn package along a predetermined passage, a knotter for knotting both yarns at a position on said predetermined passage, take-up means for taking up a twisted yarn from said delivery aperture, winding means for producing a yarn package from said yarn taken up from said delivery aperture, where the improvement cOmprises: means for reserving a predetermined length of a supplementary yarn supplied form a source and releasing it instantaneously; jet air current means for flowing an air current in the reverse direction to that of the normal running of spun yarn into said delivery aperture of the spinning rotor; means for feeding an end of yarn into said delivery aperture of said spinning rotor in the reverse direction to that of the normal running of a spun yarn when a spinning yarn is broken until said end reaches a zone affected by centrifugal force created by high speed rotation of said spinning rotor so that a piecing operation can be carried out.
 8. The improved yarn piecing and knotting apparatus according to claim 7, wherein said means of leading an end of yarn into said delivery aperture of said spinning rotor further comprises a holding device for holding an end of said supplementary yarn, and for leading said end of said supplementary yarn into said feeding device.
 9. The improved yarn piecing and knotting apparatus according to claim 8 further comprising a third suction means for temporarily reserving an excess length of loosened yarn extending from said delivery aperture to the knotter.
 10. The improved yarn piecing and knotting apparatus according to claim 9, wherein a supplementary yarn is a yarn drawn from a supplementary yarn package.
 11. The improved yarn piecing and knotting apparatus according to claim 9, further comprising: first suction means for sucking an upstream yarn delivered from said delivery aperture of said spinning rotor after the cutting of the connection between said supplementary yarn package and said supply mechanism after completion of said piecing operation, said first suction means displacing said upstream yarn along a first predetermined passage; second suction means for retrieving a broken yarn end from said yarn package and for carrying a retrieved yarn (downstream yarn) along a second predetermined passage; and, auxiliary means for shifting a portion of said downstream yarn to a position adjacent to said first predetermined passage in a parallel condition so that said knotter can be operated at a postion in said first predetermiend passage.
 12. The improved yarn piecing and knotting apparatus according to claim 11, further comprising: a carrier travelling along a predetermined carrier passage along said open-end spinning machine; detector means for detecting yarn break of any spinning units; means for stopping said carrier at a correct working position of said apparatus in front of a spinning unit where a spinning yarn is broken; program means for actuating and controlling the timing of said leading means; and retrieving means for retrieving a loosened spun yarn.
 13. The improved yarn piecing and knotting apparatus according to claim 7, wherein a supplementary yarn is a yarn drawn from the yarn package. 